1. Field of the Invention
The present invention relates to a linear guide mechanism having, for example, a base member and a slider which are provided displaceably relatively linearly.
2. Description of the Related Art
A linear guide, in which a slider is linearly displaced in the axial direction of an actuator body, has been hitherto used, for example, for a linear actuator.
Such a linear guide is disclosed in Japanese Utility Model Registration No. 2595089, in which a horizontal roller is arranged at a horizontal portion of a main slider body, and an inclined roller is arranged at an inclined portion of a side slider.
Japanese Laid-Open Patent Publication No. 11-280707 discloses a structure in which a rotary wheel is rotated while making abutment against a guide surface having a substantially V-shaped cross section formed on a side wall of a fixed section to linearly guide a movable section.
However, in the Japanese Utility Model Registration No. 2595089, the angle of intersection, which is formed by the axis of the horizontal roller and the axis of the inclined roller, is about 40xc2x0. For this reason, the floating load resistance generated upon the ceiling attachment and the lateral load resistance generated upon the wall surface attachment are decreased with respect to the vertical load resistance generated upon the horizontal attachment for the apparatus respectively. Therefore, the apparatus is deficient in isotropic load resistance for equivalently bearing the load irrelevant to the attachment posture of the apparatus.
In the Japanese Laid-Open Patent Publication No. 11-280707, there is no means for adjusting the clearance between the fixed section and the movable section at all. Therefore, it is impossible to absorb the dimensional error generated, for example, by production errors.
A general object of the present invention is to provide a linear guide mechanism which makes it possible to isotropically bear a definite load irrespective of attachment posture.
A principal object of the present invention is to provide a linear guide mechanism which makes it possible to guide a slider and a base member relatively smoothly by absorbing dimensional errors of each constitutive part.
According to the present invention, an angle xcex8, which is formed by a first load-receiving element and a second load-receiving element, has a predetermined value within a range of 45xc2x0xe2x89xa6xcex8 less than 90xc2x0, and a ratio between a load-bearing capacity RA of the first load-receiving element and a load-bearing capacity RB of the second load-receiving element has a predetermined value within a range of 1.2xe2x89xa6RB/RAxe2x89xa62.7.
Therefore, in the present invention, even when the attachment posture is changed, for example, into the horizontal attachment in which the base member is attached to a horizontal surface of an unillustrated member in a substantially horizontal state, the ceiling attachment in which the base member is attached to an unillustrated ceiling surface upside down with respect to the horizontal attachment, or the wall surface attachment in which the base member is attached along an unillustrated wall surface as a substantially vertical surface, then the ratio is substantially equivalent for the loads supported by the first load-receiving element and the second load-receiving element respectively and the respective load-bearing capacities, and thus the isotropic load resistance is achieved.
In this arrangement, a clearance-adjusting section is provided for only an inclined roller as the second load-receiving element, and the clearance-adjusting section adjusts a clearance between a roller section of the inclined roller and the inclined surface guide track. Accordingly, a certain level of the dimensional accuracy in the height direction is maintained.
Further, in the present invention, it is assumed that the angle, which is formed by an axis of a horizontal roller as the first load-receiving element and an axis of the inclined roller as the second load-receiving element, is xcex8, the load-bearing capacity of the horizontal roller is RA, and the load-bearing capacity of the inclined roller is RB. On this assumption, xcex8, RA, and RB are set so that 45xc2x0xe2x89xa6xcex8 less than 73xc2x0 and 1.2xe2x89xa6RB/RAxe2x89xa62.7 are satisfied respectively. Accordingly, the floating load resistance is substantially the same as the vertical load resistance.
When xcex8, RA, and RB are set so that 45xc2x0xe2x89xa6xcex8 less than 90xc2x0 and 1.6xe2x89xa6RB/RAxe2x89xa62.7 are satisfied respectively, the lateral load resistance is substantially the same as the vertical load resistance.
Further, when xcex8, RA, and RB are set so that 53xc2x0xe2x89xa6xcex8 less than 72xc2x0 and 1.7xe2x89xa6RB/RAxe2x89xa62.7 are satisfied respectively, all of the vertical load resistance, the floating load resistance, and the lateral load resistance are substantially identical.